1. Field of the Invention
This invention relates in general to catheters having inflatable balloons and in particular to a balloon catheter wherein the balloon is fabric reinforced.
2. Background of the Prior Art
Catheters having inflatable balloons affixed thereto are used in a variety of applications. One application for a balloon catheter is as a dilator for blood vessels which have been partially or entirely blocked by deposits on the inside wall of the blood vessel. The catheter is introduced into the affected blood vessel and the deflated balloon is maneuvered into the blocked area. By inflating the balloon, the deposits are compressed against the wall of the blood vessel, thereby opening the blood vessel to blood flow.
Because of the danger of over dilating and thereby bursting the blood vessel, it is preferred that the balloon be reinforced so that it can expand only to a predetermined maximum diameter regardless of the interior pressure applied. One balloon catheter which is so reinforced is described in British Pat. No. 1,566,674 to Hanecka and Olbert. The Hanecka balloon is reinforced by a woven synthetic fabric wherein the filaments of the fabric extend along helices of opposite sense. As stated in the patent, such a reinforced balloon shortens in length with an increase in diameter. Therefore, to prevent folds in the balloon when it is deflated, the Hanecka device employs two coaxial tubes, one slidable within the other, for lengthening the balloon when it is deflated and permitting shortening of the balloon as it is inflated. One disadvantage of such a balloon catheter is that the structure requires components or parts which are movable relative to one another.
The present invention provides a reinforced inflatable balloon which is smooth in its deflated state, yet expands in diameter without decreasing in length.